Devices may communicate with other devices via public and/or private networks. A public network, such as the Internet, may be accessible by devices, regardless of where the device resides. A private network allows devices that reside within the private network to securely communicate with one another via intra-net communication. A device within one private network may establish inter-net communication (that is, communicate with another device residing in a different network than the one it resides in) with another, remote device.
A private network may include a host and a gateway. In a private network, a host may be assigned a unique native address that may be secretive within the private network and used only by other devices within that private network. Within the private network, different hosts communicate to each other using their native addresses. The native addresses are opaque to others residing outside of the private network.
A gateway or edge router, which connects a private network to a public network such as the Internet, is assigned a unique, or potentially more than one, public address. The public address is globally visible. Therefore, the public address has meaning within a public network and may be utilized by other devices to communicate with the gateway. Devices within different private networks communicate with each other, via the public network, using public addresses. A public address of a gateway may also be associated with the hosts that reside in the same private network as the gateway.
In order for a first host located in a first private network to communicate with a second host located in a second private network (where the second private network is different than the first private network), a tunnel such as virtual private network (VPN) may be used.